Pump



l. c. JENNhlNGs March 26, 1940.

4 sheets-sheet 1 P UMP Filed Dec. 30, 1935 March' 26, 1940.

l. C. JENNINGS Filed Dec. 30, 1935 4 Sheets-Sheet 2 March 26, 1940.

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Patented Mar; 26,.

UNITED STATES PATENT- OFFICE 41 Claims.

This invention is directed to fluid piston pumps or compressors, andmore particularly to hydroturbine pumps of the type employing a rotatingwater or other liquid ring as a pumping or dis- 5 placing medium, inwhich the liquid of the ring alternately enters and recedes from aseries of displacement chambers formed as peripheral buckets in a rotorrevolving within an eccentric casing.

The well known Nash type of compressor is a good illustration of a pumphaving displacement chambers operating in a ring of liquid-and morespecifically the invention relates to improvements and developments inthe Nash pump described in United States Letters Patent to Jennings, No.1,718,294 of June 25th, 1929and No. 1,797,980 of March 24th, 1931, whichdisclose a circular rotor operating Within an eccentric casing, therotor being journaled upon tapered or conical port vmembers extendingwithin side portions of the revolving rotor. y The herein describedinvention is not limited-specifically to this type of pump, referencebeing made thereto for illustrative purposes.

Pumps of this nature have been found very satisfactory in the handlingof air and gas, al

though they willalso handle denser uids. However, it has been found thatwhile these pumps operate very satisfactorily in building up pressuresto twenty or thirty pounds gage, when it is r desired to increase thepressures above this point, there is a tendency toward leakage withinthe pump, resulting in impaired efficiency.

Running clearances between the rotor and pump casing, and between therotor and the conical port member, or members upon which it is journaledare necessary to prevent binding, and even with the greatest accuracy ofmanufacture, this clearance is enough to result in an appreciableleakage as pressures increase, unless some means is taken to prevent it.The leakage of air or gas is'of course many times greater than theleakage of a denser medium, such as a liquid, and as stated, these pumpsare frequently 55 plenishlosses thereof during normal operations,

(Cl. 23o-79) simultaneouslywith the ysealing-of the running i lclearances.

It is a further object to obtain a sealing effect of such a nature thatrunning clearances may be made much greater than heretofore, thereby re-6 ducing the cost of manufacture and increasing the efllcientlife of thepump.

Still another object contemplates a method of sealing effective toprevent leakage constantly, throughout the life of the pump, regardlessof l0 wear caused by the handlingof gritty material, or caused bycorrosion.

Another object comprises means to supply sealing liquid by recirculationof water from the discharge separator for the pump, although such 15liquid may be obtained from extraneous sources, when feasible. y

Other objects include the features of structure disclosed in theaforesaid Jennings patents, as related to the unique sealing meansforming a 20 feature of the present disclosures.

To the attainment of the foregoing and other f objects which willappear, reference may be made to the accompanying sheets of drawingsshowing certain forms and modifications of the inven-f 25 tion, and inwhich:

Fig. 1 is a section through the pumptaken on line i-l of Fig. 2; Y

Fig. 2 is a vertical transverse section taken on the line 2-2 of Fig. l;30

Fig. 3 is a reduced plan view of a pumping unit and separator,illustrating a piping arrangement for supplying sealing liquid;

Fig. 4 is a section similar to Fig. 1, but showing a modified sealingarrangement, and taken on 5 i the line t-t of Fig. 5;

Fig. 5 is a vertical transverse section taken on the line 5-5 of Fig.fi; and

Fig. 6 is a section taken on the line 6 6 of Fig. 5.

In the operation of these compressors or pumps, the liquid ring, rotatedby the rotor, follows an operating path defined by the eccentricinternal contour of the casing. The liquid first recedes from the centerof the rotor or bottom of the displacement buckets, into lobes formed onmajor axes of the casing, and this recession constitutes the suctionstroke of the compressor, drawing air, gas or other fluid which is to behandled by the pump in at the bottoms of the buckets. Then as theVperipheral portions of the buckets approach the minor axes of thecasing, the operating liquid ring is forced inward, into the bucket, toperform its compression stroke.

This action takes place several times during a` single rotation of therotor, depending upon the number of lobes formed in the pump casing. Inthe present illustration two lobes are illustrated, separated by landsat the ends of the minor axis of the casing.

Between the point where the periphery of the rotor and the casingapproach each other, and

. the point where they separate as the rotor approaches a major axis,there is built up a differential in pressure which is somewhat greaterthan the differential in pressure between the inlet to the pump and theoutlet, as built up by the compressor at its final discharge to theoutlet. Unless the rotating liquid ring'is forced into the rotor bucketsat the high pressure point without material leakage, or loss ofpressure, there w/ill be a corresponding lossin efficiency in theoperation. This leakage may occur at a number of points, and it is afeature of the present invention to minimize leakage from the highpressure points to the low pressure points, thus obtaining maximumefiiciency, and permitting the building up of higher pressuredifferentials than heretofore thought possible in pumps of this nature.

Referring now to the drawings, in which like reference numerals refer tolike parts, it will be seen that the pump comprises generally a statorIU, including an eccentric pump chamber II having enlarged portions orlobes I2 and I3, separated bylands Ill-It at opposite sides of thecasing. The line A-A illustrates a major axis of the pump chamberthrough the lobes, and the line B-B is a minor axis through the lands.

Although but two lobes are illustrated, one on either side of the minoraxis B-B, it will be obvious that the invention is applicable to pumpcasings having any desired number of lobes.

A driving shaft I5, extending through the casing, is supported bybearings Iii-I6 at either end thereof, and serves to support and drive arotor Il, of generally cylindrical shape in cross section. This rotor isprovided with a number of peripheral buckets or displacement chambersI8, formed by radial vanes I9, the outer edges of which are forwardlycurved. If desired the vanes or blades I9 may be stream-lined tofacilitate the circulation of operating liquid into and out of thebuckets.

In the preferred construction the buckets will be enclosed by shrouds2li-20, connecting the blades I9.

Extending inwardly of the chamber II are a pair of tapered hubs 2| `uponwhich the rotor is journaled, said hubs being constructed to form inletand discharge passages for the pump.

The inlet passages 22 (one for each lobe), are suitably ported as at 23for cooperation with the open bottoms of the rotor displacement bucketsI8, and the outlet or discharge passages 2t are similarly ported as at25.

At the two lands It, the spaces between the blades or vanes I9 of therotor and the casing are filled with operating liquid. As the rotor ad-`vances, the liquid is not only turned by the rotor, but also, is thrownout into the lobes by centrifugal force, and air, gas, or other mediumbeing handled, is drawn in through the ports 23. Upon furtheradvancement, the shape of the casing forces the liquid back into therotor buckets, and this liquid, acting as a piston, in each bucket,compresses and forces the gas out through the discharge ports 25.

Maximum eiliciency demands that as many as possible of the displacementchambers be at work, and therefore the space between the inlet anddischarge ports ismade as narrow as possible, opposite a land i4;preferably this spaceA occupies only a minimum of one displacementchamber.-

However, on one side of this space, as at the point 2li, the interior ofthe chamber is subjected to inlet pressures, whereas the other side issubjected,

las at the point 21, to the full discharge pressure.

thus building up a pressure differential. But inasmuch as the spacebetween the points 26 and 21 is made as small as possible, and at timesthere may be interposed but a single blade between the full dischargepressure and the lower inlet pressures, itfollows that there is greattendency for leakage across this space from point 2l to 26, due t'orunning clearance, despite the fact that the liquid ring substantiallylls the rotor buckets or chambers at these points.

There is also a `chance for leakage at various points of contact betweenthe revolving rotor and the stationary cones as indicated at the points28 and 29 (Figs. 1 and 4). Due to pressures developed in the lobesI2--I3 it is also possible that leakage will occur at the points 30,that is at the periphery of the shrouds 20.

In order to overcome, or oiset leakage at these various points, asealing liquid under pressure is distributed to such points, either froman extraneous source of supply, or by recirculation of liquid fromwithin the pump at its maximum pressure. To this end the tapered hubsvor cones 2I are lformed respectively with central passages 3 I, thewalls of which are ported as at 32, whereby sealing iiuid introducedunder pressure. to the passage 3| is free to escape to the points 26,21, 28 and 29.

Other ports 33 communicate with the space 33a between the shrouds 20 andthe interior of the pump chamber wall, whereby sealing liquid can flowto the points 30, thus taking care of all running clearances between therotor and the interior of the chamber.

This sealing water or liquid being under greater pressure than theaverage pressure in the lobes, prevents the escape of liquid from thelobes where it is doing work, into the annular space 33a between therotor and the chamber wall, which would otherwise result in somereduction in volume. This arrangement also makes possible theintroduction of make-up liquid into the lobe at the point where it willrecompense for possible loss of liquid which may be discharged throughthe outlet ports 25 with the air or other uid being pumped.

Again, the ,introduction of sealing liquid at these points makes itpossible to operate the pump with greater running clearances, thanheretofore thought necessary, without in any way aiecting the eiilciencyof the pump.

The sealing water may be introduced into the central passages 3| bymeans of piping shown particularly in Figs. 1, 3 and'4, wherein a lobeis tapped at its point of highest pressure, by a pipe 3ft. The liquid atthis point is under the greatest pressure due to the fact that the ringis forced ahead by the rotor, and forced into the rotor by the wedgingaction between the rotor and the narrowing casing. This pressure isgreater than that at the outlet ports 25, or in the discharge separator(which is substantially at the same pressure), because the water inre-entering the rotor is forced in against centrifugal force, by theforward driving effect of the blades or vanes ofv the rotor, the rotordriving the liquid into the narrowing space between the rotor and thecasing.

The pipe 34 is connected by a valve 33 to piping 33, which is tappedinto the end of a central pasextraneous source 'of liquid'underpressure, by

the valved pipe line 3l. One such source is illustrated in Fig. 3,wherein the line v3i is connected to the bottom of the dischargeseparator 38, receiving liquid which is subjected to the full dischargepressure.

Referring now particularly to Figs. 4 and 5 there will be found aslightly modified structure for providing a liquid seal. Instead of therow of ports 32, the exterior of the hub or cone 2| may be grooved at 39and du, to establish communication between the linterior of the centralpassage 3| -and the channels4 4| at the root of each individual blade orvane i3. This ensures a supply of sealing liquid from both sides of eachblade throughout the channels 4|, making an effective seal between eachside of the vanes between the ports 23 and 25. These grooves 39-40, andchannels 4| are supplied with liquid around the hub of the rotor, andthrough the ports 33, which additionally supply the annular space 33abetween the rotor and the pump chamber wall.

A similar arrangement of grooves may be used over the area of the coneindicated by the arrows X-X `(Fig. 5) between the ports 23 and 25,although a seal at this point is relatively less important than at theother points heretofore discussed, as there is a gradual distribution ofpressure over a number of blades, and the differential pressure betweenthe sides of an individual blade is not as great as is the case at thepoints 26 and 21.

Fig. 6 illustrates a modification wherein sealing water may be suppliedfrom the point of greatest pressure within a lobe, but without resort toexterior piping. In this form, the annularV space 33a between the rotorand the stator is utilized as at 30h to receive water beyond the shroud20, such water flowing through the port 33 into the central passageway3| of the hub or cone 2|. The groove 39, as heretofore, receives some ofthis water under pressure to seal the running clearance between therotor and the cone 2|.

f, In some cases it will be found desirable to introduce clean sealingliquid from an outside source under pressure, through the port 33 intothe space 33a between the sides of the rotor and the casing, allowing itto escape through the clearance at the periphery of the rotor, at thepoints 28, 29 and 30, Fig. 1. In this way extraneous material such asfiber or paper pulp, which may be handled by the compressor, isprevented from lodging between the sides of the rotor and causing unduefriction.

d Having thus described the invention, the operation and advantagesthereof will be readily apparent. Once the pump is in operation thetendencies toward leakage, which are produced by a pressure differentialbetween discharge pressures and 'intake pressures are offset bysupplying 'a sealing liquid, at a higher pressure than set up by suchdifferential, to the points'where leakage might occur. This higherpressure is obtained either by supplying liquid from an extraneoussource under a predetermined pressure, or by rei circulatingliquidiunder pressures greater than the discharge pressure, such liquidbeing obtained by tapping the interior of the pump at the point wherecentrifugal forces are being overcome by the wedging or crowding actionproduced by the converging relation between the rotor and stator.

Advantage is taken of the fact that a liquid such as water, will notleak as readily as a less dense medium such as air, and .all runningclearances are hence sealed with a liquid.

It has been found by actual test that sealing methods as described makepossible the use of double the clearance between the rotor and thestator without any reduction in volume of the medium being handled,thereby reducing manufacturing costs. It has also been found that whereheretofore it was possible to obtain up to twenty to thirty pounds gageasv a maximum for emcient operation, it is now possible to build uppressures around one hundred pounds gage. Operatlng expenses are notincreased as in the preferred form the liquid is-constantlyrecirculated; in fact, due to the increased efliciency, operating costsare actually reduced.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States, is:

1. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with an eccentric casing, and a rotor thereinhaving displacement chambers cooperative' with the pumping liquid tocreate a pressure differential between the inlet and outlet sides of thepump, of means to seal the inlet side of the pump from .the outlet sidethereof, comprising means to create and apply a pressure in oppositionto the pressure dierential of the pump, whereby to minimize leakagebetween the inlet and outlet sides of the pump.

2. In a hydro-turbine pump of the type using liquidv'in its pumpingaction, the combination with an eccentric casing, a rigid hub extendingtherewithin, and a rotor journalled on said hub and having displacementchambers cooperative with the pumping liquid to create a pressuredifferential between the inlet and outlet sides of the pump, of means toseal the'inlet side of the pump from the outlet side thereof comprisingmeans to dir ect a sealing liquid to clearances between the rotor andthe hub, and to other clearances between the rotor and the casing, inopposition to said pressure differential whereby to minimize leakagebetween the inlet and outlet sides of the i pump.

3. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination -with an eccentric casing, and a rotor thereinhaving a hub and having displacement chambers cooperative with thepumping liquid to create a pressure differential between the inlet andoutlet sides of the pump, of means to seal the inlet yside of the pumpfrom the outlet side thereof, comprising means to supply a sealingliquid at pressures at least as great as the discharge pressures in thepump and to direct said sealing liquid to rotor clearances between theinlet and outlet sides of the pump, at points spaced from the hub of therotor whereby to minimize leakage at such points. l

4. In a hydro-turbine pump of thetype using liquid in its pumpingaction, the combination with an eccentric casing, and a rotor thereinhav- `ing displacement chambers cooperative with the pumping liquid tocreate a pressure differential between the inlet and outlet sides of thepmp,

of means to seal the inlet side of the pump from the outlet sidethereof, comprising means to direct a sealing liquid to the clearancespaces bemajor axis and a land along a minor axis, and a rotor thereinhaving displacement chambers cooperative with the pumping liquid tocreate apressure differential between the inlet and outlet y sides ofthe pump, of means to withdraw part of the pumping liquid from said lobeand to return same to-the casing adjacent said land, and to direct saidliquid as it returns to clearance spaces between the rotor and thecasing at a pressure at least as great as the pressure diil'erentialgenerated within the pump whereby to. minimize leakage between the inletand outlet sides of the Dumll 6. In a hydro-turbine pump of the typeusing liquid in its pumping action, the combination with an eccentriccasing having a lobe along a major axis and a land along a minor axis,and a rotor therein having displacement chambers cooperative with thepumping liquid to create a pressure differential between the inlet andoutlet sides of the pump, of means to withdraw part of the pumpingliquid from said lobe at the point of 'greatest pressure in the lobe andtoreturn -same' to clearance spaces between the rotor and thecasing at apressure at least as great as the pressure diierential generated withinthe pump whereby to minimize leakage between the inlet and outlet sidesof the pump.

7. The combination in a pump of the type using liquidI in its pumpingaction, of a lobe casing and a rotor therein having displacementchambers cooperative with the pumping liquid, of means to controlleakage between the inlet and outlet sides of the pump, comprising meansto supply a sealing liquid to points of leakage andl ential of the pump,to running clearances be-,

tween said rotor and hub, in opposition to-the normal pressuredi'erential of the pump, substantially centrally thereof, and adjacentthe ends of the hub, including a uid receiving passage extending throughthe hub and ports effective to establish communication between saidpassage and the rotor.

9. In a hydro-turbine pump, the combination with a casing having a hubextending inwardly thereof, inlet and discharge passages extendingthrough said hub, a rotor journalled on said hub and having displacementchambers, said chambers and hub being formed with cooperating portsforinlet to and discharge from the pump, of means for directing a sealinguid to running clearances between said rotor and hub, including a uidreceiving passage extending through the hub, said hub being providedwith uid receiving grooves on its external surfaces, means establishingcommunication between said grooves and said uid receiving passage, andsaid rotor being journalled across said grooves.

10. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with an eccentric casing having a ported hub, ay

directing the liquid, and said rotor being Journalled across saidgrooves.

11. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with an eccentric casing having a ported hub, arotor turning on said hub and having peripheral displacement' chamberscooperative with the pump liquid and the ported hub, of means fordirecting a sealing liquid to running clearances between said rotor andhub, said hub being provided with fluid receiving grooves on itsexternal surfaces, means establishing communication between said groovesand said means for directing the liquid, and means for directing asealing liquid to those points of the casing closest to the periphery ofthe rotor.

12. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with a lobe casing and a rotor in said casinghaving peripheral displacement chambers cooperative with the pumpingliquid, of separating means connected' to the discharge of the pump,-and means to supply a sealing liquid from said separating means topoints of leakage between the inlet and outlet sides of the pump,whereby to minimize such leakage, cool the pumping liquid and make uplosses in said pumping liquid. Y i

13. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with an eccentric casing having a ported hub, arotor turning on said hub and having peripheral displacement chamberscooperative with the pumping liquid and the ported hub, of means fordirecting a sealing liquid, in opposition to the normal pressure.dierential 'of the pump, to those points of the casing closest to theperiphery of the rotor,`and means for directing a sealing liquid to therunning clearances between said'rotor and hub.

14. In a hydro-turbinepump of the type using liquid in its pumpingaction, the combination with an eccentric casing having a lobe, and arotor in said casing having displacement chambers cooperative with thepumping liquid to create a pressure diierential between the inlet andoutlet sides of the pump, of means to withdraw part of the pumpingliquid from said lobe at the point of greatest pressure therein andreturn same to points of leakage between the inlet and outlet sides ofthe pump, including a conduit extending from said point of greatestpressure in the lobe-to said points of leakage.

15. In a hydro-turbine pump, an eccentric casing, a rotor operativetherein, an inlet region and an outlet region, means including saidrotor to develop pressures in the discharge region greater than those inthe inlet region, and means to direct a sealing liquid, in opposition tosaid developed pressures, to intermediate points between said inletand'outlet regions whereby to reduce leakage therebetween.

16. In a hydro-turbine pump, an eccentric casing, a rotor operativetherein, an inlet region and an outlet region, means including saidrotor to develop pressures in the discharge region greater than those inthe inlet region, and means -to direct a sealing liquid to intermediatepoints between said inlet and outlet regions, at a higher pressure thanthe pressure differential of said regions whereby to reduce leakagetherebetween.

17. The method of sealing a rotary liquid ring pump against leakagebetween the inlet and outlet regions which comprises withdrawing aportion of the liquid of said ring from the point of highest pressure ina lobe of the pump, and recirculating same by directing said portion toa point of leakage, under pressure and in opposition to ow of liquidpast said point.

18. In a hydro-turbine pump of the type using liquid in its pumpingaction, a stator provided with passages for the reception of sealingliquid, a tapered hub within the stator, a rotor cooperative with saidhub, means establishing communication between said passages and runningclearances between said rotor and hub, and between said passages andrunning clearance adjacent the,periphery of said rotor, and means tointroduce liquid Vunder pressure to said passages, whereby to seal allof said running clearances between said rotor and stator againstleakage.

19. In a hydro-turbine pump of the type using liquid in its pumpingaction, a stator provided with passages for the lreception of sealingliquid, a tapered hub within the stator, a rotor cooperative with saidhub, means establishing communication between said passages and runningclearances between said rotor and hub, and between said passages andrunning clearance adjacent the periphery of said rotor, means tointroduce liquid under suflicient pressure, to said passages to seal allof said running clearances between said rotor and stator againstleakage, and to force some of said liquid through said clearances,whereby to make up losses in pumping liquid and to lower the operatingtemperatures of the pump.

20. The method of sealing a rotary liquid ring pump against leakagebetween inlet and outlet regions at points approximating maximum pumppressures. supplying losses in operating medium and maintaining lowoperating temperatures,-

which comprises recirculating a portion of the operating medium underpressures at least as -ereat as the maximum pressure developed in themir/1p past said points and back to the main bcdv of operating medium.

21. In a hydro-turbine pump of the type using lnuid in its pumpingaction, the combination with an eccentric casing, a'hub extendingtherewithin. and a r'otor journalled on said hub and having pump vanesdening displacement chamhers cooperative with the pumping liquid tocreate a pressure differential between the inlet and` outlet sides ofthe pump, of means to seal the inlet side of the pump from the outletsidethereof, comprising means to direct a sealing liquid to clearancesbetween the rotor and the hub, and

other clearances between the rotor and the casing, in opposition to Saidpressurel differential whereby to minimize leakage between vthe inletsaid hub and said rotor adjacent the bases of said vanes. l

22. In a hydro-turbine pump of the type using liquid in its pumpingaction, the combination with an eccentric casing, a hub extendingtherewithin, and a rotor journalled on said hub and having pump vanesdefining displacement chambers cooperative with the pumping liquid tocreate a pressure differential between the inlet and outlet sides of thepump, of means to seal the inlet side of the pump from the outlet sidethereof, comprising means to direct a'sealing liquid to clearancesbetween the rotor and the hub, and to other clearances between the rotorand the casing, in opposition to said pressure dierential whereby tominimize leakage between the inlet and outlet sides of the pump, saiddirecting means including channels extending respectively along theroots of the individual vanes.

23. In a hydro-turbine pump, the. combination with a casing having aported hub, inlet and discharge, passages extending through said hub, arotor journalled on said hub and having blades forming displacementchambers cooperativewith the ported hub, of means for directing asealing fluid to running clearances between said rotor and hub, andacrossfthe surfaces of said blades, including channels extendingrespectively along the roots of the individual blades, whereby tominimize leakage within the chamber past'said clearances.

24. In a hydro-turbine pump, the combination with a casing having a hubextending inwardly thereof, inlet and discharge passages extendingthrough said hub, a rotor journalled on said hub and having vanesforming displacement chambers, said chambers and hub being formed withcooperating ports for inlet to and discharge from ,the pump, of meansfor directing a sealing duid to running clearances between said rotorand hub, including a fluid receiving passage extending through the hub,said hub being provided 'with fluid receiving grooves on its externalsurfaces, and said rotor being channeled along theH respective bases ofsaid vanes, said rotor being journalled across said grooves.

25. In ahydro-turbine pump of the type using y a sealing liquid to therunning clearances between said rotor and hub, said directing meansincluding channels extending respectively along the roots of theindividual vanes.

26. -In a wet type gas pump employing a liquid piston arranged forrotation within a piston chamber, a rotor, a port member extending intothe sides of said rotor and having inlet and outlet ports communicatingtherewith, and a passage to conduct water from the piston chamber to theperipheral surface of said port member and direct it into the spacesbetween the contiguous surfaces of said port member and said rotor.

27. In a wet type gas pump of the type employing a liquid piston, acasing, a rotor mounted within said casing, port members extending intothe sides of said rotor and having inlet and outlet ports communicatingtherewith, a conned body of sealing water disposed peripherally of eachsaid -port member to provide a seal between contiguous surfaces of therotor andthe port mem;

` bers, and means to replenish said body of water to make up lossestherefrom.

28. In a wet, type gas pump employing a liquid piston, a casing, a rotormounted therein and having a multiplicity of vanes dening a plurality ofdisplacement chambers, each of said vaneshaving a groove in its-innerface, a port member having inlet and outlet ports communicating withsaid rotor and having a sectional groove in its peripheral surface, saidrst mentioned groove and said sectional groove being in communicationwhen said varies are contiguous with the surface of said port member,and means to supply sealing water to said groove.

29. In a wet type gas pump of the type employing a liquid piston, acasing, a rotor mounted.

within said casing, port members extending into the sides of said rotorand having inlet and outlet ports communicating therewith, a sectionalgroove in the peripheral surface of each said port member, and means tosupply sealing water to said grooves.

30. In a wet type gas pump of the type employing a liquid piston, acasing, al rotor mounted within said casing, port members extending intothe sides of said rotor and having inlet and outlet ports communicatingtherewith, a confined body of sealing water disposed peripherally ofeach said port member intermediate said inlet and outlet ports toprovide a seal between contiguous sur- :t'aces of the rotor and the portmembers, and means to replenish said body of water to make up lossestherefrom.

3i. In a hydro-turbine pump .of the type using liquid in its pumpingaction, a stator 'provided with passages for the reception oi' sealingliquid,

a rotor cooperative with said stator and effective to create a pressuredifferential between the inlet and outlet sides oi' the pump, meansestablishing communication between said passages and running clearancebetween the rotor and stator, remote from the periphery of the rotor,and means to introduce sealing liquid to said passages, under pressuregreater than said pressure differential, whereby to seal all of saidrunning clear' ances against leakage.

32. In a hydro-turbine pump of the type using liquid in its pumpingaction, a stator provided with passages for the reception of sealingliquid, rotor supporting means within the stator, a rotor cooperativewith said supporting means, means establishing communication betweensaid passages and running clearance between the rotor and its supportingmeans', and between said passages and running clearance adjacent theperiphery of said rotor, andmeans to introduce sealing liquid underpressure to said passage, whereby to seal all of said running clearancesbetween said rotor and stator against leakage.

33. In a hydro-turbine pump of the type using lliquid in its pumping'action, a stator provided with passages for the reception of sealingliquid, a rotor cooperative with said stator, and eiective to create apressure differential between the inlet and outlet sides of the pump,means establishing communication between said passages and runningclearances between the rotor and stator, and means to introduce sealingliquid to said passages, in opposition to said pressure dierential, andunder pressure at least as great as said pressure differential, wherebyto seal said running clearances against leakage.

34. In a hydro-turbine pump of the type using liquid in its pumpingaction, a stator provided with passages for the reception of sealingliquid, a port member, a rotor cooperative with said port member,`arranged to revolve within the stator, means establishing communicationbetween said passages and running clearances between the rotor and saidport member, and means to introduce sealing liquid under pressuregreater than the normal pressure diierential of the pump, to saidpassages, whereby to seal said running clearances against leakage.

35. In a pump of the type using liquid for its displacing medium, astator, a port member in said stator, a rotor cooperating with said portmember, said rotor being provided with shrouds having a close runningclearance with the stator,

` the casing, in opposition to the normal pressure differential of thepump, whereby to seal the running clearance between the periphery of theshrouds and the stator.

36. In a pump of the type using liquid for its displacing medium, astator, a port member in said stator, arotor cooperating with said portmember, and rotatable within the stator for pumping purposes, and meansto introduce sealing liquid under pressure greater than the normalpressure differential o'f the pump, to inner points of running clearancebetween the port member and the rotor, whereby to seal said runningclearance;

37. Ina pump of the type using liquid for its displacing medium, astator, a port member in said stator, a rotor cooperating with said portmember, land rotatable within the stator for pumping purposes, saidrotor being provided with shrouds having a close running clearance withthe stator at their periphery, and means to introduce sealing liquidunder pressure between the shrouds and the casing, and to inner pointsoil `passages for the reception of sealing liquid, a

rotorcooperative with said stator and effective to create a pressuredifferential between the inlet of one lobe and the outlet of an adjacentlobe, means establishing communication between said passages and runningclearances between the pressure at least as great as said pressuredifferential, whereby to seal said running clearances against leakage atpoints opposite the lands.

39. In a hydro-turbine pump of the type using liquid in its pumpingaction, a stator formed with a pumping lobe and a land therefor, saidstator beingprovided with passages for the reception of sealing liquid,a rotor cooperative with said stator and eiective to create a pressurediilerential between the inlet and outlet sides of the pump, meansestablishing communication between said passages and running clearancesbetween the rotor and stator at the land, and means to introduce sealingliquid to said passages under pressure at least as great as saidpressure differential, whereby to seal said running clear-v meansincluding a lobe and a land operativelyl co-operative with said firstpumping means, and rotor means eiective to create a pressure diierentialbetween the inlet of one lobe and the outlet of the other lobe, andmeans to introduce sealing liquid to points between said inlet of onelobe and said outlet of the other lobe under pressure at least as greatas said pressure diierential,

whereby to seal said inlet and outlet against leakage therebetween.

4l. In a hydro-turbinepump of the type using liquid in its pumpingaction, a lobe casing having a pumping lobe, and an inlet region and anoutlet region, a rotor operative in said casing, and means to seal thepump against leakage between the inlet and outlet regions, includingmeans to withdraw a portion of the pumping liquid from the point ofhighest pressure in the lobe of the casing and recirculate same bydirecting said withdrawn portion of the liquid to a point ofleakage inthe lobe casing, under pressure, and in opposition to'ilow of uid pastsaid point.

IRVING C. JENNINGS.

CERTIFICATE OF CORRECTION Patent No. 1195,17@ AMarv-ch 26, 19LLo.

IRVING c. JENNINGS.

It is hereby certifiedthat error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page LL,first column, lines 59 and 60, claim8, strike out the Words and comma"in oppo- Isition to the normal pressure differential of the pump," andinsert the same after the word and comma "hub," in line 62, same claim;and that the said Letters Patent should be read With this correctiontherein that the same may conform to the record of the case inthe PatentOffice.'

Signed and sealed this 7th day of May, A. D. 1911.0.

` Henr5r .Van Arsdale,

(Seal) Acting Commissioner of Patents.

